package leetcode;

import java.util.HashSet;
import java.util.Set;

public class LeetCodeMain95 {

}
class Trie {
    private Trie[] children;
    private boolean isEnd;
    public Trie() {
        children=new Trie[26];
        isEnd=false;
    }

    public void insert(String word) {
        Trie node=this;
        for (int i = 0; i < word.length(); i++) {
            char ch=word.charAt(i);
            int index=ch-'a';
            if (node.children[index]==null){
                node.children[index]=new Trie();
            }
            node=node.children[index];
        }
        node.isEnd=true;
    }

    public boolean search(String word) {
        Trie node=searchPrefix(word);
        return node!=null&&node.isEnd;
    }

    private Trie searchPrefix(String word) {
        Trie node=this;
        for (int i = 0; i < word.length(); i++) {
            char ch=word.charAt(i);
            int index=ch-'a';
            if (node.children[index]==null){
                return null;
            }
            node=node.children[index];
        }
        return node;
    }

    public boolean startsWith(String prefix) {
        return searchPrefix(prefix) != null;
    }
}
